The subject invention concerns a turbine runner of the Kaplan type with adjustable runner blades, where the runner blades are adjustable by an oil-operated servo-motor, which is mounted on a piston rod in the runner hub.
Oil-operated servomotors are often used in Kaplan turbines for the purpose of adjusting the runner blades. Leakage losses of the servo-oil from the servomotor may occur. Due to the increasing environmental requirements, the leakage losses of the servo-oil must be prevented from being transported to the medium flowing around the turbine.
Therefore, the subject invention is based on the task of defining a turbine runner with which the leakage from the servomotor can be prevented, in a simple and effective manner, from being transported into the medium flowing around the turbine.
According to the invention, this task is solved by a collecting bin being provided in which the oil emerging between the piston rod and a seal of the servomotor is collected, the collecting bin being arranged around the free end of the piston rod and rigidly connected with the servomotor and moving with the latter, a delivery pipe being provided and one end of the delivery pipe discharging into a pump room formed between the movable collecting bin and the fixed piston rod and the actuation movement of the servomotor reducing and increasing the pump room and thus hydraulic liquid being conveyed from the collecting bin into the delivery pipe.
In this manner, the power for conveying the leakage from the runner comes from the servomotor during the adjustment movement of the runner blades, and, therefore, no separate driving mechanism is needed for the leakage conveyance system. The movement of the servomotor, which is in any case needed to control the turbine, is therefore used for conveying the leakage as well. In addition, the leakage conveying system is of simple design and needs but a few items and requires only minor adaptations to the runner.
It is especially easy to prevent backflow of the leakage into the collecting bin by providing a valve in the delivery pipe.
A particularly advantageous embodiment is achieved with an intermediate storage for the conveyed oil, which is accommodated in the turbine runner, wherein the intermediate storage is advantageously arranged between the piston rod, the runner hub and a turbine shaft to which the turbine runner is mounted.
To enable ease of conveyance of the leakage from the intermediate bin, a second delivery pipe, which is preferably arranged in the turbine shaft, is provided, the end of which is connected to the intermediate bin.
Backflow of the leakage from the intermediate storage to the collecting bin can be prevented easily by the discharge of the first delivery pipe being arranged in the intermediate storage such that the level of the leakage is below the discharge of the first delivery line.